Antimicrobially modified, biaxially oriented polyester films are known.
WO 2002/062577 describes polyester films anti-microbially modified using triclosan. The migration of triclosan from PET is very slow, however, and effective antimicrobial action is therefore possible only with high loadings. Triclosan is moreover a chlorinated organic compound, which can react further during the regrinding process (e.g. of the film edge trims arising in the film production process) to give potentially toxic chlorine compounds. Triclosan is, moreover, undesirable in many applications for environmental reasons and because of the risk of development of resistance.
WO 2006/000755 describes polyester films equipped with a zirconium phosphate comprising silver ions. Because of the layer structure of these phosphates, only small gaps are available for escape of the silver, and this likewise means that relatively high loadings are necessary for effective defense from microorganisms.
U.S. Pat. No. 5,556,699 describes polymer films equipped with a zeolite containing silver ions. Although polyesters are mentioned as suitable polymer substrates, no polyester films are described in the Examples. The patent describes suitable zeolites in various sizes, which were introduced into films with different layer structure. The polymers used for the films described moreover also exhibited a fall-off in antimicrobial action at a zeolite particle size in the region of the thickness of the layer equipped with said zeolite.